A lithium air battery has a weight energy density of about 500 Wh/kg or more which is much higher than that of the current lithium ion battery (200 Wh/kg) or the next generation lithium ion battery (300 Wh/kg). Thus, many researches are underway into the lithium air battery for electric vehicles capable of long-distance driving with a single charge.
A positive electrode of the lithium air battery shows a different discharge capacity depending on the type of carbon. This is because shape and amount of Li2O2, a discharge product, are changed depending on geometry of pore and structure of the carbon. Among carbon blacks known until now, ketjen black is known as a carbon electrode having the highest capacity. However, problems of the lithium air battery that overvoltage is large during charging and cycle life is short cannot be completely solved by using the ketjen black.
Thus, the research for increasing discharge capacity of the positive electrode and lowering overvoltage during charging/discharging is one of the important themes in the study of the positive electrode for developing a method of increasing capacity and cycle life of the lithium air battery.